We will study RNA and protein metabolism in hypothalamus and pituitary in ovariectomized rats after estrogen treatment and during the rat estrous cycle. In addition, the pattern of incorporation of Unidine-H to the third power into subcellular portions of pituitary and hypothalamus under these experimental conditions will be examined. We are now testing the hypothesis that estrogen facilitates the formation of "releasable" LH in the pituitary. We hope to complete these investigations in 1976. BIBLIOGRAPHIC REFERENCES: Kalra, S.P. Circadian rhythm in luteinizing hormone-releasing hormone (LH-RH) content of preoptic area during the rat estrous cycle. Brain Res. 104:354, 1976. Kalra, S.P. Tissue levels of luteinizing hormone-releasing hormone in the preoptic area and hypothalamus and serum concentration of gonadotropins following anterior hypothalamic deafferentation and estrogen treatment of the female rat. Endocrinology (To appear in July, 1976).